vercel-zig

Zig runtime for Vercel Serverless Functions. Compiles Zig projects and deploys them as native provided.al2023 Lambda functions with zero cold start overhead.

Quick Start

Add to your vercel.json:

{
  "builds": [
    {
      "src": "main.zig",
      "use": "vercel-zig-runtime"
    }
  ],
  "routes": [
    { "handle": "filesystem" },
    { "src": "/(.*)", "dest": "/main" }
  ]
}

Your Zig project needs a build.zig with a vercel build step that produces a bootstrap binary targeting x86_64-linux. The binary must implement the AWS Lambda custom runtime API (poll AWS_LAMBDA_RUNTIME_API for events).

Configuration

| Option | Default | Description | |--------|---------|-------------| | buildStep | "vercel" | Zig build step name | | binaryName | "bootstrap" | Output binary name in zig-out/bin/ |

{
  "builds": [
    {
      "src": "main.zig",
      "use": "vercel-zig-runtime",
      "config": {
        "buildStep": "docs-vercel"
      }
    }
  ]
}

How It Works

1. Downloads and caches Zig 0.15.2 on first build
2. Cross-compiles your project for Linux x86_64
3. Packages the binary as a native provided.al2023 Lambda function
4. Caches .zig-cache between deploys for faster rebuilds

No Node.js, no shims, no runtime layers. The Zig binary runs directly on Lambda.

Build Step

Your build.zig needs a step that the runtime can invoke. By default it looks for vercel:

const vercel_exe = b.addExecutable(.{
    .name = "bootstrap",
    .root_module = b.createModule(.{
        .root_source_file = b.path("src/main.zig"),
        .target = b.standardTargetOptions(.{}),
        .optimize = b.standardOptimizeOption(.{}),
    }),
});
const vercel_step = b.step("vercel", "Build for Vercel");
vercel_step.dependOn(&b.addInstallArtifact(vercel_exe, .{}).step);

License

Apache 2.0